Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
If a host has a valid IP address and subnet mask but no default gateway, what is the most likely result?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
The host can usually reach only local-subnet destinations and not remote networks.
This is correct because the host has no next hop for off-subnet traffic.
B
Distractor review
The host cannot use ARP at all.
This is wrong because ARP is still used for local Layer 2 resolution.
C
Distractor review
The host automatically joins every subnet in the LAN.
This is wrong because a missing gateway does not change subnet membership.
D
Distractor review
The host becomes the default gateway for other devices.
This is wrong because host settings do not automatically make the host a router.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is assuming that a host without a default gateway cannot use ARP or communicate at all. This is incorrect because ARP is used for local Layer 2 address resolution and remains functional. Another trap is believing the host automatically joins other subnets or becomes a gateway for others, which does not happen. The key mistake is confusing local subnet communication with remote network access. The default gateway only affects off-subnet traffic, so the host can still communicate locally but fails to reach remote destinations.
Technical deep dive
How to think about this question
A host on an IP network requires several key configuration elements to communicate effectively: a valid IP address, a subnet mask, and a default gateway. The IP address and subnet mask allow the host to determine which IP addresses are within its local subnet and which are outside. The default gateway acts as the next-hop router for any traffic destined for remote networks beyond the local subnet. Without a default gateway, the host cannot forward packets to devices outside its subnet. When a host sends traffic, it first checks if the destination IP is within its subnet by applying the subnet mask. If the destination is local, the host uses Address Resolution Protocol (ARP) to resolve the MAC address and sends the frame directly. If the destination is off-subnet, the host forwards the packet to the default gateway's MAC address. If no default gateway is configured, the host has no route to reach remote networks, causing communication failures beyond the local subnet. This behavior often confuses learners who assume that a host without a default gateway cannot communicate at all. However, local subnet communication remains functional because ARP and direct Layer 2 forwarding still operate. The exam trap lies in misunderstanding the role of the default gateway, leading to incorrect assumptions about ARP usage or subnet membership. Practically, missing a default gateway breaks only off-subnet communication, a critical concept for CCNA routing and IP services understanding.
KKey Concepts to Remember
- A host uses its subnet mask to determine whether a destination IP address is local or remote before sending traffic.
- The default gateway provides the next-hop IP address for forwarding packets destined to remote networks outside the local subnet.
- Without a default gateway, a host cannot forward packets to off-subnet destinations, causing remote communication to fail.
- Address Resolution Protocol (ARP) is still used by the host to resolve MAC addresses for local subnet communication even without a default gateway.
- A missing default gateway does not change the host’s subnet membership or IP addressing but limits routing capabilities.
- Hosts do not automatically become default gateways for other devices simply because they lack a configured gateway.
- Local subnet communication relies on Layer 2 forwarding and ARP, which remain functional without a default gateway.
- The default gateway setting is essential for routing traffic beyond the local subnet, a fundamental concept in IP services and routing.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Related practice questions
Related 200-301 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
A host uses its subnet mask to determine whether a destination IP address is local or remote before sending traffic.
What is the correct answer to this question?
The correct answer is: The host can usually reach only local-subnet destinations and not remote networks. — The host will normally reach local destinations but fail to reach remote networks. In practical terms, the subnet mask still lets the host identify what is local, but without a default gateway it has no next hop for off-subnet traffic. That means local ARP-based communication can still work, while remote communication usually fails. This is a core host-configuration concept and a very common certification question. The missing gateway does not break all communication — it breaks off-subnet communication.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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